“I was in way over my head with the surgeries,” Pratt, 29, tells PEOPLE exclusively. “I had no idea what I was getting into or that it was a lifelong commitment. It was very challenging, both physically, emotionally, spiritually, mentally, on my husband and on our lives.”

In fact, Pratt, 29, admits, “It was a huge turning point for us in such a negative way. There was a fallout with The Hills and a lot of backlash with the things we were doing. We spent more money and it was so unnecessary. Sometimes I can’t believe I did that to us and to me. It’s been a lot to overcome.”

Heidi and Spencer Pratt

Andrew Southam

For exclusive photos and more from Heidi and Spencer, pick up the new issue of PEOPLE, on stands Friday.

Still, the reality star says, “I don’t want to say I regret it 100 percent because I’ve tried to grow from it.”

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“They were so heavy they were falling through the skin,” she says. “It was just too heavy for my body and I was in pain and uncomfortable all the time. I thought, ‘What do I need this big of breasts for?’ ”

Now healthy and happy, “my priorities have shifted,” Pratt says. “I think it’s important not to pigeonhole yourself in past mistakes but to learn from them and move on.”